Touch screen panels generally comprise an insulative (e.g., glass) substrate and a resistive layer disposed on the insulative substrate. A pattern of conductive edge electrodes are then formed on the edges of the resistive layer. The conductive electrodes form orthogonal electric fields in the X and Y directions across the resistive layer. Contact of a finger or stylus on the active area of the panel then causes the generation of a signal that is representative of the X and Y coordinates of the location of the finger or stylus with respect to the substrate. In this way, the associated touch panel circuitry connected to the touch panel by wiring traces can ascertain where the touch occurred on the substrate.
Typically, a computer program generates an option to the user (e.g. “press here for ‘yes’ and press here for ‘no’”) on a monitor underneath the touch screen panel and the conductive electrode pattern assists in detecting which option was chosen when the touch screen panel was touched by the user.
The application referred to above relates to an improved edge electrode pattern on the resistive layer of the touch screen panel. The instant application relates to an improvement in the prior art wiring harnesses attached to the touch screen.
There are typically four insulated individual wires, each extending along and around the edges of the touch screen panel to each corner of the touch screen panel where the insulation is removed and the wire is hand soldered to a terminal electrode on the panel at each corner of the panel.
One or more additional layers, usually tape, are often used to secure the wires to the edges of the panel and there may be an insulative layer between the wires and the edge electrodes of the panel to electrically isolate the wires from the edge electrodes.
The problem with such prior art devices are numerous. The solder joints are often not very reliable and create solder bumps on the smooth surface. Moreover, the act of soldering the ends of each wire to the corner electrodes can damage the electrodes or even crack the substrate of the touch panel. Also, this assembly process is labor intensive and hence costly.
To reduce noise, a noise shield may be place under the wires. Adequate noise protection, however, may not always be possible. Also, the assembled touch screen panel does not have a finished appearance. Instead, the taped on wires are bulky and readily noticeable and detract from the appearance to the touch screen panel.